I need help solving this:

Question

The grams of protein in 1 cup of soup that has 110 Cal with 7 g of fat and 9 g of carbohydrate.
Express your answer using one significant figure.

Thanks
-MC

Answer 1

For this one-
The grams of sugar (carbohydrate) in one can of cola if it has 140 Cal and no fat and no protein.
Express your answer using one significant figure.

Is the answer 40 once rounded to sig figs?
Thanks

Answer 2

Are you using the same values I am for grams fat, grams protein, grams carbs?
Total Cal = g fat + g carb + g protein.
110 Cal = (7*9) + (9*4) + (4*g carb)
g carb = (110-63-36)/4 = 2.75 which is rounded to 3.00 and to 1 s.f. is 3 grams. Of course you know that 110 Calories = 110 kcal.

Answer 3

For the cola drink:
If you're using 4 Cal/g carb, then
140/4 = 35 g carb which I would round to 40 and to 1 s.f. that is 4 x 10^1 or 4E1.
I don't know what 40 once means.